The number of vehicles travelling in Australian cities has grown almost tenfold in the past 70 years and, with exponential population growth not being met with adequate road infrastructure upgrades, traffic speeds are crawling to a standstill.

Growth in metropolitan travel has increased significantly across the decades, with annual passenger kilometres travelled in the eight capital cities growing from 3.5 billion in 1900 to almost 199 billion by 2014.

Last year, a report from the Committee for Economic Development of Australia said congestion could cost the nation more than $50 billion in lost productivity by 2031 unless addressed.

The latest congestion bill was $16.5bn in 2015.

Congestion levels on major arterial roads are at a high, with most cities suffering much slower travel times and lower average speeds than previously recorded.

READ MOREMyths around great urban chokeEAN HIGGINSNew roads ‘won’t free up cities’EAN HIGGINS, EMILY RITCHIESydney, which last year was named the nation’s most congested city by peak transport body Austroads, has seen significant reductions in average speeds even since 2011. The population of Greater Sydney has risen by almost 300,000 people during that time, reaching almost five million.

The average speed on the Warringah Freeway, which connects northern Sydney to the CBD, has decreased by 13.7km/h towards the city during morning peak and decreased by 10.4km/h outside of peak hours. On Southern Cross Drive, a motorway that leads from Botany in the city’s south into the city’s east, average speeds have decreased by 10km/h into the city and 2.4km/h southbound. And on Victoria Road, which connects Parramatta with the western end of the Anzac Bridge, the average speed has decreased by 3km/h towards the city during morning peak and 3.7km/h out of the city during afternoon peak hours.

Last year’s Aust­roads Congestion and Reliability report found Sydney was host to seven of Australia’s 10 slowest roads, with Melbourne and Adelaide containing the remaining three.

While Adelaide’s King William Street came out on top as Australia’s slowest thoroughfare with an average speed of 13.5km/h, Harris Street in Sydney’s inner-city suburb of Pyrmont ranked second as drivers crawled along at 14.5km/h. The other Sydney roads to feature in the top 10 slowest were Lane Cove Road, Epping Road, Homebush Bay Drive, the Eastern Distributor and Cahill Expressway.

Sydney is also home to seven of the nation’s most delayed roads and drivers need to account for 50 per cent additional travel time during peak hours to arrive at their destination on time.

Another sign of the mounting pressures of a booming population is the average speed of 72.5km/h on Sydney’s road network — which includes motorways such as the M7 and M2 — which is even slower than New York. Roads and Maritime NSW hopes when the controversial $17bn WestConnex project is complete, travel times on the M4 Motorway will be cut by 74 per cent, potentially saving motorists close to 15 minutes on a morning peak city-bound trip, with an average 19-minute trip cut to four minutes.

Sydney and Melbourne have similar congestion patterns due to similar population levels and number of vehicles on the roads.